[SI-LIST] Re: RF board Vs High speed board ... RF amplifiers

  • From: "Andrew Burnside" <Andrew.Burnside@xxxxxxxxxxxxxxxxxxx>
  • To: <si-list@xxxxxxxxxxxxx>
  • Date: Wed, 24 Aug 2005 21:37:45 +0100

Glenn
 
Fair enough, but these bandwidths are still much greater than the 20kHz cited. 
Group delay is still a problem, maybe not as bad as a 10GHz digital system, but 
still worth consideration, especially if running higher order modulation 
schemes.
 
As an illustration of larger RF bandwidths, electronics warfare systems can 
easily have 10-20GHz of received bandwidth per antenna. The RF front end then 
may channelise this, to more manageable bandwidths e.g 1-2GHz, but somewhere on 
the RF board there will still be the full bandwidth.
 
Andrew
 
 
________________________________

From: glenn_wood@xxxxxxxxxxx [mailto:glenn_wood@xxxxxxxxxxx]
Sent: Wed 24/08/2005 18:33
To: Andrew Burnside; si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Re: RF board Vs High speed board ... RF amplifiers



Does anyone know of any off the shelf parts that can *linearly* amplify Ultra 
Wideband Signals and with a F3dB as high as 10GHz?  Actually, in this case, the 
carrier can be considered to be 2.5GHz and the bandwidth extends down to 500MHz 
(or 0.2 of carrier).

Thanks

-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx
[mailto:si-list-bounce@xxxxxxxxxxxxx]On Behalf Of Andrew Burnside
Sent: Wednesday, August 24, 2005 11:05 AM
To: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Re: RF board Vs High speed board


Hi Lynne/John

RF signals are not necessarily narrowband.
For example, Ultra Wideband Signals (becoming more common these days) have a 
bandwidth of at least 0.25 of the carrier frequency.

The other case that wideband RF is often seen on boards these days is in Direct 
Digital Downconversion architectures. You might see in excess of 1GHz going 
into ADCs, and that's only the IF! In this case the wideband IF often contains 
several signals.

Usually some steps have been taken by the implementer of an RF system to limit 
the bandwidth, similar to pre-emphasis and de-emphasis in a high speed digital 
system. So usually the RF board will have slightly more rounded signals, but 
these may have higher rms power than the high speed digital system, especially 
in a PA subsystem.

Regards

Andrew


________________________________

From: si-list-bounce@xxxxxxxxxxxxx on behalf of Lynne D. Green
Sent: Wed 24/08/2005 17:27
To: johnnfaq@xxxxxxxxx; si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Re: RF board Vs High speed board



Hello, John,

RF signals are "narrow band", i.e. modulation is superimposed on a carrier
frequency.  The modulation bandwidth is significantly smaller than the
carrier frequency (your car radio is a good example - carrier is around
100kHz, bandwidth is around 20kHz.)  RF requires filtering to remove the
carrier and recover the signal.

High-speed signals are "wide band", i.e. they have significant frequency
content from DC to hundreds of times the modulation rate.  For an ideal
interconnect, filtering is not required to recover the original signal.
(And, although rates are usually given in MHz, they really mean Mbaud.)

Best regards,
Lynne


"IBIS training when you need it, where you need it."

Dr. Lynne Green
Green Streak Programs
http://www.greenstreakprograms.com
425-788-0412
lgreen22@xxxxxxxxxxxxxx

-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On
Behalf Of johnn william
Sent: Wednesday, August 24, 2005 4:19 AM
To: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] RF board Vs High speed board

Hi All,

Please anyone in group clarify the difference in handling the RF board
compared to normal High speed boards.

Thanks in advance.

John


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